3M Bondo Wood Filler 30 oz (850.49 g) with Bondo Cream Hardner 0.5 oz (14g), Repairs Chips and Cracks in Wood, Sandable, Paintable, and Stainable (WF-QT-ES)

I am restoring old French windows and the wood needed a lot of patching, reinforcing and rebuilding. I had never used Bondo wood filler, but everyone assured me it was the best product for the job. The results are fantastic, but what a MAJOR pain in the neck Bondo is to use! First, you need to figure out how much of the tiny tube of hardener to use for the big quart of filler. After watching a bunch of YouTube videos, I got the idea, and the fact that I went through the entire quart of filler and had just a tiny bit of hardener left probably means I got the ratio about right. If you’ve never used Bondo, I highly recommend watching the videos — you really do need just a tiny bit of hardener for the small amount of Bondo you can reasonably use before it hardens. I also bought the pink Bondo spreaders (https://www.amazon.com/dp/B000BOC9K4) because one video said that the Bondo spreaders are the color that the mixed filler/hardener should be. Either that video was using a different formulation or Bondo changed the color of the hardener — it’s blue, not red, so when you mix it, you’re aiming for a sickly, light-green color. Even so, for a few bucks, the Bondo spreaders worked quite well; they’re stiff enough to mix the Bondo thoroughly and apply it, but have just enough flexibility to help smooth the product (which, based on my experience, is definitely an skill that requires a fair amount of practice). You need to mix this in very small batches (at most, a few tablespoons at a time) because each batch must be used in literally 2-3 minutes. When time is up, the mixture quickly starts caking and getting hard, making it utterly useless. And on the topic of mixing, I ended up mixing it on an 8”x10” piece of acrylic, which is non-porous (so it won’t soak up any of the oils in the product), sturdy to mix the heck out of the two components quickly, and perfectly smooth, which makes clean-up much easier after each batch. And yes, you need to clean the mixing board and the utensils after each batch; otherwise, your next batch could be contaminated and your spreaders will be caked with hard Bondo which will prevent smooth spreading of the next batch. As for the results, they are amazing, despite the TOTAL PITA this product is to use. The product can fill deep holds solidly, but can also build up pretty delicate shapes (sometimes requiring 4-5 thin layers and lots of sanding to get perfect). It really does dry hard in 15-20 minutes and is easily sandable. If Bondo would just invent an additive that would increase the working time — even by a few minutes — this would be a lot easier and less frustrating to work with. As it is, however, it is a total pain to use, but worth the effort given the excellent results. Final note: Be sure to wear thin gloves (thin latex/surgical gloves) when mixing and applying the Bondo. However careful you think you can be, Bondo will end up on your fingers and it is absolutely miserable to remove! 5 (begrudging) stars.

This is a high quality very strong filler. It fills and holds extremely well. It is easy to get in to a complicated hole or edge and is easy to sand. BUT - the fumes and dust are toxic. I have to wear a mask if I don't have very good ventilation (like from moving air). It is like two part fiberglass resin/catalyst which stinks terrible and is actually dangerous. Small amounts are fine and larger if well ventilated as I said. I used my respirator with organic solvent filters if I was doing much of it. The big issue is that it cures very, very fast. Even if you spread it out which is a trick you can do with a lot of fiberglass resins. This sets fast so you can't really use it slowly or do large areas at the same time. It is easy to mix though. I think I used too much of the catalyst at times which will make it cure too fast. You have to eyeball how much to use though so that is easy to do. If I used it more often I would be able to calibrate the amounts by eyeball better. I do like it though. It does a good job for permanent jobs. The fast setting means you don't have to wait for it to cure. It may be too fast if you need more time to fill and work it. Easy to sand. Sands smooth. It cures a medium green and my latex primer didn't hide it very well so plan on using a high-hide primer/paint. I didn't need to drill and tap for screws or bolts but I suspect it will be pretty good at that. Whether it would be as strong as wood I'm not sure but it may actually be stronger. Recommended if all this sounds right for you.

I had a lot of checks in my deck boards. I needed something which would hold up to rain. This product hardens quickly so there was a learning curve to how little to mix at a time. I ended up putting paste and hardener in the fridge overnight. Cooling the product increases the working time. It is easy to mix and apply. I scraped excess off so sanding was minimal. I used Cabot deck stain and there is no hint of the Bondo underneath. It was tedious to mix numerous small batches but the results were worth it. I gave 4 stars instead of 5 because I don’t know how it will hold up.

I work in my work shop on alot of wood projects. Wood is not as good as it used to be and is expensive. I reuse pieces of wood alot and this works good to fill imperfections like nail holes etc. Dries fast to move things along. I have put some sawdust in the product when mixing if I plan on staining the wood. Works great.

Had a lot of wood filling to do and needed something really tough. This does a really good job of filling, smoothing sanding and priming. The only real drawback is the extremely short working time. You really gotta move quick! This has a tendency to sag on vertical surfaces so you have to work the product as it starts to stiffen up. The warmer the day, the faster it hardens. you have almost no working time in direct sun in the summer. I was told putting the unmixed can in the refrigerator helps with increasing working time, but makes it harder to mix the harder in.

It worked great for my deck. When using it go light on the hardener or it will harden before you can spreed it out. when applying it on Long deep cracks give it time even after sanding it, because it may crack or shrink, just apply a thin coat over it and sand it smooth and your good. I also used wood hardener that petrifies wood before applying the filler. With enough work and patients you'll have great results!

I used this wood filler to repair my rotted wood door. I am very happy with this two-component material. it is very strong and water resistant, it is perfect for outdoor application. it can also be sanded and painted. one thing you need to pay attention is this material hardens evry quicky after mix, within 3~4 min, so you need apply it quickly before it hardens. I will repurchase it in future.

We have received only 3 pieces. Ordered quantity was 5pcs.

Very good, exactly as explained in the ad

This stuff works great but you need to work very fast as it hardens up in just a few minutes so you need to work in very small batches. Keep in mind that this stuff is extremely smelly to use which isn't a problem outdoors but i don't recommend it for indoors due to the odor. I find this product very good as it hardens so well but I find it overpriced for what it is.

This stuff is very good for fixing exterior wood damage, rotted wood etc, big voids, etc. Works good, but move fast, after mixing 2-3 minutes it will start to harden up, and you wont be able to spread out. Works just like bondo for a car, but made for wood. Also go easy on the hardner, doesn't take much, from a video I watched, a 3" Circle of bondo, 1/2" thick should use 1 line of hardner across the 3" circle, but this might be to much. It works really well, sandable, fills big voids, just very fast working time, and doesn't need much hardner.